SUEZ (Paris) has announced the inauguration of the new biogenic CO2-recovery unit derived from anaerobic digestion of biowaste at SUEZ’s Terres d’Aquitaine site in Saint-Selve, Gironde. On this occasion, SUEZ also announced the European certification of its digestate, marking a first in France. These significant advancements position this Gironde-based platform as a benchmark for the circular economy, driving the energy and agricultural transition in local territories. Suez also recently opened a novel waste-treatment plant in Sète, France, which produces renewable energy while treating wastewater.
With an annual production capacity exceeding 45 GWh of biomethane—a local and renewable energy source injected into the gas distribution network of the company GRDF—3,500 tons of biogenic CO₂ recovered locally, and 100% of solid digestate converted into certified soil amendments for agricultural use, Terres d’Aquitaine provides the region with a concrete, circular and locally integrated solution.
The Terres d’Aquitaine site, operated by SUEZ since 2006, is dedicated to the recovery of organic waste. This includes biowaste from supermarkets, local authorities, the agri-food industry, as well as agricultural residues produced within the Nouvelle-Aquitaine region. In addition to its work in waste collection and promoting sorting practices, SUEZ now integrates all stages of biowaste recovery at this single site. These stages include material separation, anaerobic digestion, composting, the production of biogas and high-quality digestates, which are then distributed to end users. Centralising the entire biowaste transformation process in one location ensures optimal performance, quality, and traceability.
Since its creation, Terres d’Aquitaine has undergone numerous developments and received support from the Nouvelle-Aquitaine Region and ADEME. SUEZ has invested more than €22 million to anticipate and meet the needs of local authorities and businesses, as well as regulatory changes.
Anaerobic digestion is a sensitive biological process that can be affected by both internal and external factors, such as the quality of incoming waste, temperature fluctuations, or the presence of inhibitors. To ensure optimal performance of the site’s facilities, SUEZ uses advanced intelligent management systems and cutting-edge artificial intelligence tools. These technologies enable real-time analysis of incoming materials, early detection of process deviations, and optimisation of biogas production. This innovative approach guarantees stable operations and consistent high-quality outputs.
As an operational showcase, the site combines industrial expertise, continuous innovation, and strong local engagement. It demonstrates SUEZ’s commitment to positioning anaerobic digestion as a strategic cornerstone of a high-value-added circular economy, driving the energy transition and supporting the sustainable development of local communities.
SUEZ is going one step further by launching a biogenic CO₂ recovery unit to provide a new solution for the valorisation of by-products from the anaerobic digestion of biowaste, in line with a fully circular approach. Operational since May 2025, this cutting-edge technology will complement the range of solutions already implemented at Terres d’Aquitaine, ensuring the entire organic waste value chain is addressed.
Co-funded by the Nouvelle-Aquitaine Region with a contribution of €560,000, representing 40% of the total investment, this facility will ultimately enable the recovery of up to 3,500 tonnes of biogenic CO₂ per year from the biowaste processed on-site.
The biogas produced through anaerobic digestion is purified to remove impurities and separate the biomethane from the CO₂. This CO₂ is then captured, purified, and liquefied on-site using V’COOL technology, which was developed by SUEZ’s partner, PRODEVAL. This renewable CO₂ is sold under a contract with Rougeline, an association of six agricultural cooperatives in southern France. It is already being used by two vegetable producers in the Landes region to enhance the photosynthesis of greenhouse-grown tomato plants, as a replacement for fossil CO₂. This provides a tangible solution for improving agricultural yields while reducing the carbon footprint of greenhouse farming. Additional local applications could also be explored, such as CO₂ fire extinguishers, algae production, or refrigeration for the food industry.
Since January 2025, the solid digestate (a by-product of the anaerobic digestion process of natural organic matter or organic residues) produced at Terres d’Aquitaine, has been awarded a new European certification, recognising its high agronomic value. This secured and rigorously controlled product expands the range of solutions available to farmers for soil enrichment, reducing reliance on chemical inputs. Over 9,000 tonnes of certified digestate will be sold annually by TERRIAL, a SUEZ/AVRIL joint venture, under an exclusive agreement, benefiting local stakeholders.
In addition, SUEZ and TERRIAL are continuing research efforts to develop fertilizing materials at the Terres d’Aquitaine site and combine the benefits of organic soil improvers and fertilisers to support plant growth and protect soil health, even in challenging environments or areas affected by drought.